Synapses are most fundamental to the function of a nervous system. C. elegans is an excellent genetic model system for finding genes and elucidating pathways because of its sequenced genome and the abundance of molecular biology tools and mutants. Due to the simplicity of its nervous system, many breakthroughs have been made in C. elegans for understanding molecular mechanisms in the patterning of the nervous system and synapse development. The current bottlenecks, however, are in the manual and non-quantitative techniques such as visual screens, often limiting both the throughput of the experiments and the phenotypes one can examine. Our long-term objective is to develop technologies to understand how genes, age, and the environment together define and continue to remodel the nervous system of an organism. Microtechnologies are ideal for studies of C. elegans neuroscience because of the relevant length scales and the possibility for automation; similarly quantitative imaging techniques are key to deciphering molecular mechanisms. The objective of this R01 project is to engineer micro devices for large-scale live imaging and quantitative imaging technologies in order to study synapse development in an in vivo system. Genes and pathways emerging from this study could potentially become targets of therapeutics in neurological disorders. We hypothesize that quantitative microscopy-based approaches can indeed enable identification of novel genes and pathways that conventional approaches cannot. The first component of this project is to develop on-chip rapid and high-content in vivo imaging techniques, and in parallel to develop algorithms and quantitative measures for the analysis of such high-content data. The second component of the project is to perform screens and studies using these novel technologies. The approach is innovative because the technology developed here dramatically increases the capabilities of existing imaging and screening tools by several orders of magnitude in speed and much more sensitive and accurate than conventional manual approaches. The proposed research is significant because it fills the urgent need in high-throughput and high-content screens as well as identifying novel genes and pathways. In addition, besides the contribution to the specific neurobiology, the technologies are widely applicable to areas such as developmental cell biology, and to other small organisms such as fly larvae and zebrafish embryos.